2000 Pajero IO(4G93 / H76W) intermittently fails to go past 2000rpms

My Pajero IO has been behaving strangely lately. I will drive it for about 20kms at speeds of 80-100km/h without any problem but once I get to a hilly section of the road the engine fails to accelerate beyond 2,000rpms. When this happens I will park by the roadside, disonnect and then reconnect one of the battery terminals and voila I am good again until this issue recurs.

It's quite annoying especially when I am driving long distances as I am forced to do this 101 times. I have had the high pressure fuel pump replaced twice but the problem won't go away. I had someone do some diagnosis on it and the results showed that a few sensors could be faulty: air temparature sensor, air flow sensor, fuel pressure sensor & barometric pressure sensor.

Any one of you guys had a similar experience and how did you resolve it?

Thanks.